I'm interested in teaching ESL in Germany (I'm an American) and would eventually want to start a small business. I've read that German work permits often have restrictions placed on them, and that if one wants to start a business, these restrictions must be removed, which may or may not be possible.

For those with ESL-related jobs, is it possible to start a business with your work permits? If not, can those permits be changed so as to allow one to start a business? Thanks for any replies.